The FR4 variant uses CWDM4 wavelength multiplexing across a duplex LC fiber pair. Four wavelengths carry 100G each, delivering 400G aggregate over standard SMF. Full spec table below:
| Parameter | Value |
|---|---|
| Form Factor | QSFP-DD (Double Density) |
| Data Rate | 400G (4 x 100G) |
| Modulation | PAM4 |
| Fiber Type | Single-Mode Fiber (SMF) |
| Connector | Duplex LC |
| Reach | 2 km |
| Wavelengths | 1271 nm / 1291 nm / 1311 nm / 1331 nm (CWDM4) |
| TX Power (typical) | -6.5 to +4.5 dBm per lane |
| RX Sensitivity (max) | -8.6 dBm per lane |
| Power Budget | ~7 dB |
| Max Power Consumption | 10W |
| Operating Temperature | 0°C to 70°C (commercial) |
| DDM / DOM Support | Yes (Tx power, Rx power, temperature, voltage, bias current) |
| Standards Compliance | IEEE 802.3bs, CWDM4-OIF MSA |
DDM support is worth highlighting specifically. On Juniper JunOS, you can pull real-time per-lane Tx and Rx power, temperature, and bias current with show interfaces diagnostics optics. A compatible module that correctly implements DDM gives you the same operational visibility as the OEM part — no blind spots.
When a module is inserted, JunOS performs a vendor ID check against the EEPROM data at link-up. If the vendor name, part number, or checksum doesn't match an entry in the platform's approved list, the port may generate an alarm, log an "unsupported transceiver" warning, or in some configurations refuse to bring the link up entirely.
This is not a hardware incompatibility. It's a software check against stored vendor strings.
A properly coded compatible module rewrites the relevant EEPROM fields — vendor name, vendor part number (VPN), vendor serial number format, and checksum bytes — to match what JunOS expects. The optical performance of the module is unchanged. The link comes up clean, DDM data reports correctly, and no alarm fires.
Before ordering any "Juniper-compatible" FR4, verify the following:
Suppliers with genuine OEM/ODM capability — including custom firmware coding — can deliver modules with all of these fields correctly set before they ship. That eliminates the on-site reprogramming step that causes most post-delivery compatibility failures.
Both FR4 and DR4 are 400G QSFP-DD modules for single-mode fiber, but they are not interchangeable. The differences have real consequences for your cabling infrastructure and use case.
| Attribute | QSFP-DD FR4 | QSFP-DD DR4 |
|---|---|---|
| Fiber | Duplex LC (2 fibers) | MPO-12 (8 fibers) |
| Reach | 2 km | 500 m |
| Wavelength scheme | CWDM4 (4 x 100G WDM) | 1310 nm (4 x 100G parallel) |
| Existing SMF plant | Works with standard LC runs | Requires parallel SMF or MPO |
| Typical use case | Inter-building, campus core, DCI edge | Within-building, top-of-rack to spine |
| Splitter/mux support | Yes (passive CWDM mux) | No |
Choose FR4 when your runs exceed 500 m, when your cabling plant is built on duplex LC SMF, or when you need to multiplex multiple 400G links over a shared fiber pair using passive CWDM mux gear.
Choose DR4 when you're connecting within the same building, your MPO infrastructure is already in place, and 500 m reach is sufficient.
On Juniper QFX5220 deployments connecting distribution switches across a campus, FR4 is almost always the right call. On PTX10000 spine-to-leaf runs inside a single data hall, DR4 is typically more practical.
Juniper's list price for the JNP-QSFP-DD-400G-FR4 sits around $2,260 per module at standard reseller pricing. At that rate, equipping a 32-port QFX5220 with 400G FR4 uplinks costs over $72,000 in optics alone — before cabling or installation.
Compatible 400G QSFP-DD FR4 modules coded for Juniper platforms are available in the $100 to $660 range depending on supplier, volume tier, and testing level. At the midpoint, that's roughly 85% savings against OEM list.
| Quantity | OEM Juniper (per unit est.) | Compatible (per unit est.) | Savings |
|---|---|---|---|
| 1 unit | ~$2,260 | ~$500–660 | ~70–78% |
| 10 units | ~$2,260 | ~$300–500 | ~78–87% |
| 50+ units | ~$2,260 | ~$100–300 | ~87–96% |
Those savings compound quickly. A 50-module order at compatible pricing versus OEM can free up $80,000 to $100,000 in a single procurement cycle — real budget that can go toward additional ports, spares, or infrastructure elsewhere.
Factory-direct pricing removes the distributor markup that resellers build into compatible module pricing. That's the structural reason per-unit cost drops further at volume, and why sourcing directly from a supplier with manufacturing relationships matters.
The following Juniper platforms accept 400G QSFP-DD FR4 modules. Compatible modules must be coded to each platform's expected vendor string.
| Platform | Form Factor Slot | JunOS Version | Notes |
|---|---|---|---|
| QFX5220-32CD | QSFP-DD | 20.2R1+ | 32 x 400G QSFP-DD ports |
| QFX5220-128C | QSFP-DD | 20.2R1+ | 128 x 100G or 32 x 400G |
| PTX10003 | QSFP-DD | 19.4R1+ | Line card dependent |
| PTX10008 | QSFP-DD | 19.4R1+ | FPC slot dependent |
| PTX10016 | QSFP-DD | 20.1R1+ | High-density spine |
| MX10004 | QSFP-DD | 21.1R1+ | MPC10E line card required |
Always confirm the specific JunOS version running on your chassis before ordering. A compatible module coded for QFX5220 may require a different vendor string than one coded for PTX10003. A supplier with platform-specific testing capability can verify this before shipment.
Standard lead times for compatible 400G QSFP-DD FR4 modules from factory-direct suppliers run 3 to 7 business days for in-stock quantities. Custom-coded or OEM/ODM orders with specific Juniper vendor strings typically add 5 to 10 business days for EEPROM programming and pre-shipment testing.
For bulk orders above 50 units, request:
For procurement cycles above 100 units, white-label and OEM/ODM options become worth evaluating. Custom-branded modules with your company's vendor string or a private-label PN are available from suppliers with ODM capability — which matters if you're a VAR or regional distributor building margin into a resale program.
HYTOPTODEVICE covers 400G QSFP-DD across FR4, DR4, SR8, and LR4 variants, with Juniper-compatible coding available. The catalog spans 1.25G to 800G, so you're not assembling a multi-vendor BOM when a deployment requires mixed speeds.
A few specifics relevant to FR4 Juniper procurement:
If you're specifying FR4 modules for a QFX5220 or PTX10000 build and want to confirm Juniper coding before ordering, create an account at hytoptodevice.com to access pricing tiers and technical support.
Q1: Will a 400G QSFP-DD FR4 compatible module work in a Juniper QFX5220 without generating unsupported transceiver warnings?
A: Yes, provided the module's EEPROM is correctly programmed with the Juniper-expected vendor string, part number, and checksum. A properly coded compatible module brings the link up clean with no alarms and full DDM visibility in JunOS.
Q2: What is the reach of the 400G QSFP-DD FR4, and what fiber does it require?
A: The FR4 supports 2 km over single-mode fiber using a duplex LC connector. It uses CWDM4 wavelength multiplexing at 1271, 1291, 1311, and 1331 nm. It does not work over multimode fiber.
Q3: How does FR4 differ from DR4 for Juniper deployments?
A: FR4 uses duplex LC with CWDM4 WDM and reaches 2 km, making it suited for inter-building and campus runs. DR4 uses an MPO-12 connector with four parallel 1310 nm lanes and reaches 500 m, making it better for within-building spine-to-leaf links. They are not fiber-compatible with each other.
Q4: What is the price difference between Juniper OEM and compatible 400G QSFP-DD FR4 modules?
A: Juniper OEM pricing for the JNP-QSFP-DD-400G-FR4 is approximately $2,260 per unit at standard reseller pricing. Compatible modules coded for Juniper platforms range from roughly $100 to $660 depending on volume and supplier — representing 70 to 96% savings depending on order size.
Q5: Does the compatible FR4 module support DDM on Juniper JunOS?
A: Yes. A correctly implemented compatible module supports DDM per SFF-8636 / CMIS 4.0, allowing JunOS to report per-lane Tx power, Rx power, temperature, supply voltage, and bias current via show interfaces diagnostics optics.
Q6: Can I order 400G QSFP-DD FR4 modules with custom Juniper coding for a white-label or VAR program?
A: Yes. Suppliers with OEM/ODM capability, including HYTOPTODEVICE, can program custom vendor strings and part numbers for reseller or white-label programs. This is relevant for VARs and regional distributors who need to maintain their own part number scheme while delivering Juniper-compatible modules to end customers.
show interfaces diagnostics optics without blind spots.
